Ellmore Timothy M, Beauchamp Michael S, O'Neill Thomas J, Dreyer Stephen, Tandon Nitin
Department of Neurosurgery, The University of Texas Medical School at Houston, Texas 77030, USA.
J Neurosurg. 2009 Oct;111(4):755-66. doi: 10.3171/2009.3.JNS081427.
Maps produced using either electrical stimulation or functional imaging have demonstrated a distributed network of cortical regions involved in expressive and receptive language tasks. The pattern of connectivity among components of this network has begun to be explored with diffusion tensor (DT) imaging, but has yet to be completely characterized. In this study the authors used DT imaging-based tractography to examine the interrelationship between cortical areas found to be essential for language by intraoperative electrical stimulation.
The authors localized the arcuate fasciculus (AF), a white matter fiber system connecting frontal and parietotemporal areas in 10 patients, 9 of whom subsequently underwent left hemispheric language mapping.
The authors found that 81 (79%) of 102 essential language sites (ELSs) were closely related to the AF. Of all ELSs, 59% were located within 7.5 mm of AF fiber pathway terminations, and another 20% contained pathways terminating closer to the AF than would be expected by chance (p < 0.05). Additionally, direct subcortical stimulation of the AF following focal cerebral resections produced transient language deficits. The close spatial relationship found between ELSs and the AF suggests that tractography data alone may be used for localization of ELSs.
The deficits evoked by subcortical stimulation validate and demonstrate the utility of this AF localization technique, and provide further evidence that the AF is an important pathway for fluent language. Taken together, these results demonstrate that DT imaging of the AF may be used to predict the location of brain areas that will be eloquent by the standards of stimulation mapping.
使用电刺激或功能成像生成的图谱已显示出参与表达性和接受性语言任务的皮质区域分布网络。该网络各组成部分之间的连接模式已开始通过扩散张量（DT）成像进行探索，但尚未完全明确。在本研究中，作者使用基于DT成像的纤维束成像来检查术中电刺激发现的对语言至关重要的皮质区域之间的相互关系。
作者在10例患者中定位了弓状束（AF），这是一种连接额叶和顶颞叶区域的白质纤维系统，其中9例患者随后接受了左半球语言图谱绘制。
作者发现，102个基本语言位点（ELSs）中的81个（79%）与AF密切相关。在所有ELSs中，59%位于AF纤维束通路终点7.5毫米范围内，另外20%包含比偶然预期更靠近AF的终止通路（p < 0.05）。此外，局灶性脑切除术后对AF进行直接皮质下刺激会产生短暂的语言缺陷。ELSs与AF之间紧密的空间关系表明，仅纤维束成像数据可用于ELSs的定位。
皮质下刺激引起的缺陷验证并证明了这种AF定位技术的实用性，并进一步证明AF是流畅语言的重要通路。综上所述，这些结果表明，AF的DT成像可用于预测按照刺激图谱标准将具有语言功能的脑区位置。
